Prolinamides containing 2-(2-aminocyclohexyl)phenols as highly enantioselective organocatalysts for aldol reactions.

Effective synthesis of prolinamides of 2-(2-aminocyclohexyl)phenols has been accomplished. The novel prolinamides are demonstrated to catalyze the direct aldol reaction between ketones and aldehydes with high stereoselectivity, thus affording up to 99 : 1 anti/syn diastereomeric and 99 : 1 enantiomeric ratio. Experimental results as well as computational investigations have revealed that the electrophile (e.g. aldehyde) is activated by dual hydrogen bonding with the amide NH and phenolic OH group of the catalyst. A rather large spacing between the H-bond donor groups and its conformational flexibility are remarkable structural features of the most enantioselective catalyst.

A DFT study on nitrotriazines.

In this study, all possible mono-, di- and tri-nitro-substituted triazine compounds have been considered as potential candidates for high-energy density materials (HEDMs) by using quantum chemical treatment. Geometric and electronic structures, thermodynamic properties and detonation performances of these nitro-substituted triazines have been systematically studied using density functional theory (DFT, B3LYP) at the level of 6-31G(d,p), 6-31+G(d,p), 6-311G(d,p), 6-311+G(d,p) and cc-pVDZ basis sets. Moreover, thermal stabilities have been evaluated from the homolytic bond dissociation energies (BDEs). Detailed molecular orbital (MO) investigation has been performed on these potential HEDMs. According to the results of the calculations, mono-, di- and tri-nitro-substituted derivatives of symmetric 1,3,5-triazine have been found to be more stable than their 1,2,3 and 1,2,4 counterparts.

Computational studies on nitratoethylnitramine (NENA), its tautomers and charged forms.

An energetic material, nitratoethylnitramine (NENA), its tautomers and also its charged forms are considered quantum chemically, using various basis sets at the levels of ab initio and density functional theories (DFT). NENA has been found to be sensitive to negative charge development, resulting in rupture of ONO(2) bond. Also conformational and molecular dynamics (MD) studies have been performed on NENA. Various geometrical parameters, energies and infrared spectra have been obtained and discussed. Also, calculations indicate that s-cis conformation of NENA is slightly more stable than the s-trans and the tautomers of it have very comparable total energy values to NENA. On the other hand, on the basis of homolytic bond dissociation energies (BDE) for ONO(2) bond in the structures, it is clear that the presence of the tautomers in the bulk of NENA somewhat should decrease its sensitivity.

Quantum chemical treatment of cyanogen azide and its univalent and divalent ionic forms.

An explosive material, cyanogen azide (CN4) and its univalent and divalent anionic and cationic forms have been studied quantum chemically by using different theoretical approaches. In this study, the structures considered have been screened for their relative stabilities. Also, they have been investigated whether the charged forms play a role in the usual explosion process or any electrical charging during storage cause explosion. Various quantum chemical properties are obtained and discussed. It has been found that the univalent cation and anion and divalent cation formations do not cause much change in the molecular structure as compared to the neutral cyanogen azide molecule, whereas the divalent anionic form exhibits drastic changes in the geometry, resulting in bond cleavage to eliminate nitrogen molecule.

Quantum chemical study on 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) and some of its constitutional isomers.

Presently, certain isomeric compounds of NTO and their tautomers have been investigated by performing density functional theory (DFT) calculations at B3LYP/6-31G(d,p) and ROB3P86/6-311G(d,p) levels and also ab initio calculations at RHF/6-311G(d,p) level. The optimized geometries, vibrational frequencies, electronic structures and some thermodynamical values for the presently considered NTO isomers have been obtained in their ground states. Also, detonation performances were evaluated by the Kammlet-Jacobs equations, based on the calculated densities and heat of formation values. The homolytic bond dissociation energies (BDEs) (at ROB3P86/6-311G(d,p) level) of NNO(2) and CNO(2) for the molecules were calculated. Moreover, aromatic character of NTO and its isomers and tautomers were investigated by performing NICS calculations using the gauge invariant atomic orbital (GIAO) approach at the B3LYP/6-31G(d,p) and B3LYP/cc-pVDZ levels.

Ab initio and DFT study on 1,4-dinitroglycoluril configurational isomers: cis-DINGU and trans-DINGU.

cis-1,4-Dinitroglycoluril (1,4-dinitrotetrahydroimidazo[4,5-d]imidazole-2,5-(1H,3H)-dione, C(4)H(4)N(6)O(6), known as DINGU in the literature) is an important explosive regarded as one of the potential ingredients for LOVA (low vulnerability ammunition) applications. However, there is no study concerning trans-DINGU, to the best of our knowledge. Thus, in the present study the structural and electronic properties of the configurational isomers of DINGU (cis- and trans-isomers) have been investigated by performing density functional theory (DFT) calculations at B3LYP/6-31G(d,p), UB3LYP/6-31G(d,p) levels and also ab initio calculations at RHF/6-31G(d,p) and UHF/6-31G(d,p) levels. The optimized geometries, vibrational frequencies, electronic structures, and some thermodynamical values for the presently considered DINGU isomers have been obtained in their ground states. Comparing the calculated energy data (total electronic energy, heat of formation values and homolytic bond dissociation values of N-NO(2)) and the calculated bond lengths, cis-DINGU was found to be a more stable molecule than the trans-isomer.